In a turbine engine, an intermediate casing is a structural element of the engine and it comprises a hub supporting the shafts of the various rotors of the turbojet. An outer annular casing is connected to the hub of the intermediate casing via radial connection arms that serve in particular to transmit some of the forces between the engine and its support, and also via a plurality of outlet guide vanes (OGVs) that serve to straighten out the secondary stream along the axis of the engine.
The presence of connection arms within the intermediate casing leads to significant aerodynamic disturbance for the outlet guide vanes. These outlet guide vanes (there typically being 30 to 50 of them) must therefore accommodate the aerodynamic disturbance caused by the connection arms. For this purpose, the geometrical profiles of these vanes vary gradually all around the circumference of the OGV wheel. By way of example, for an OGV wheel having 40 outlet guide vanes, it may be necessary to use seven to ten different geometrical profiles.
Furthermore, it is known to have recourse to composite materials for making various parts of an aviation turbine engine. Such a part may thus be obtained by making a fiber preform and by densifying the preform with a matrix. Depending on the intended application, the preform may be made of glass, carbon, or ceramic fibers and the matrix may be made of an organic material (polymer), or of carbon, or of ceramic. Reference may be made to international patent application PCT/FR2012/052853 filed on Dec. 10, 2012, which describes an example of fabricating outlet guide vanes out of composite material.
The use of N different geometrical profiles for making a single turbine engine OGV wheel makes it necessary to multiply by N the steps of fabricating outlet guide vanes out of composite material, thereby correspondingly increasing the cost and the duration of fabricating the OGV wheel.